View of Spitfire K9834 modified as the Type 323 High-Speed Spitfire at Eastleigh, Southampton in 1939. Notice the blunt wingtips, the streamlined Perspex windscreen, the four-bladed fixed-pitch wooden propeller and the tail-skid in place of the usual tailwheel. Later restored to a more conventional configuration, it served throughout the war as a station "hack" with PRU.
During the winter of 1937/8 the 48th production Spitfire, K9834, was cleaned up and fitted with a Rolls-Royce Merlin III (sprint Merlin) which, on test, recorded 2,160 h.p. with 27lb boost. The four-blade, course pitch wooden propeller was 10ft in diameter.

The 2,160 h.p. Merlin II Special being worked upon at Eastleigh.

Another view of N.17 in its original form. The deeper radiator is more apparent in this view. The Merlin Special developed 2,160 r.p.m. for short sprint periods running on 100-octane fuel.